Exercise 6, spring 2006
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Templates

	In previous exercise a double linked list and a binary tree for integers were examined.
If now only examining the double linked list, what if one would like to have a double linked list 
that would store, say, doubles - what modifications would have to be done to the code? For example 
examine the code of DLlist::Remove()-method(see the example code for that exercise) - how would
you change it if the list contained doubles instead of ints and how the type of stored
data is visible there? Examine also the rest of the code 
of double linked list and think what parts would remain practically the same and 
what would work even though the list would store doubles, or some other type.

You may notice that the code would be essentially the same. So surely there is a way to use the 
existing code for the list of doubles? Indeed there is - only 'minor' modifications are needed 
to make it a template-class, which enables not only the use of doubles, but many other types as 
well.

So, here's the task: modify the double linked list class to template class, and test it 
with a main program - create lists of different type (int, double, etc.). 



Some remarks about templates:

-The syntax can be quite tricky, but try not to put all the concentration on getting the syntax 
correct, but instead try to see the idea. Also with template classes, the class methods should 
be written to the same header file where the class is defined.

-There are differences between compilers, meaning for example that a code that compiles fine
with some compiler, results to loads of error messages with some other compiler - this may
happen especially with templates. So don't be surprised if a code that works with, for example, 
Dev-c++ doesn't work with visual c++ 6.0(used in exercises), or the other way round, although
this might not be a problem with very basic template-syntax.